Datsun Roadster Forum-311s.org

Hey everyone. It's been a while since I have been very active on the board. Took a new job in late September after 30 years with my employer. Leaving to join my competitor. Long story short have been traveling a lot and working 50-60 hour weeks leaving little time to enjoy the company of my roadster friends.

My car has suddenly started running like crap. It will randomly start running rough at idle and and then just stop, like I turned off the ignition. I can get it to continue running if I start giving it throttle. Driving is just fine. Good smooth acceleration, good power, but when I return to idle, it just stops. But not every time. I'll be sitting at a light, idling just fine, and then just stop, like I turned the ignition off. Then rough and sputtery.

2L, brand new solexes, GB Dizzy, MSD coil. New Motor. Everything has about 2300 miles on it. I can see nice clean fuel in the inline filter, so I know I am getting fuel.

Thanks my friends!

Kyle

It looks like the thing to do would be to determine what quits first. If you can duplicate it in the driveway, get a test light on the coil + to indicate primary ignition, and a timing light on a plug wire to show spark.

Don't take this as gospel, but from my experience, if it ONLY cuts out at idle, the odds are it isn't the ignition without there being other running problems, like misfire etc.

Does it start right back up or do you need to crank it for a while ? If you need to crank, might be lack of fuel in the carbs, but I'm not overly familiar with Solex.

Sounds like crap in the idle or transition ports...

That's what I'm thinking too Sid. Time for a carb cleaning.

Cheers
James

What is the idle at just before it dies? It could be that you need to readjust your idle stop. Mine does this every so often when I come off track. Some how the idle screw backs off I will say this only happens some times and only after being hammered around a track at very high rpm.

If you idle is really low, you might try bringing it up a little bit. You might also pull each of your jet blocks and make sure you don't have a loose jet. I've had fuel jets vibrate out of the jet blocks in the past.

Will

Will reminded me, also check your throttle cable, make sure it has slack, and if your car has a hand throttle, make sure it is fully off. If the idle screws are not hitting the stops, from a cable holding them back, when they do close, it may be too far.

Thanks for the tips. I'll try a couple of these ideas out in between rain showers. Will, I tried the idle first. Bumped it up to 1100 RMP and still dies. I can keep giving it throttle and keep it running. Would low pressure at the fuel pump be something to look at as well? Brand new fuel pump. (Aftermarket) Maybe a higher RMP produces more pressure?

I wouldn't think I need a carb cleaning. Brand new solexes, right out of the box with 2,300 miles on them. I'll pull all the jets, inspect, clean and replace.

I'll let you know if anything helps. I don't know if it could be anything electrical, but my electronic tach is all over the place. Only gets to the proper RPM reading when I apply throttle. When decelerating, the needle bounces all over the place. I have ordered a new under dash voltage regulator as I think that may be the culprit. The original one did not work, so I took it apart, cleaned and rebuilt. I think my repair has now failed.

Kyle

Kyle,
The fuel pump is likely good. You only need a maximum of 4.5 lbs of pressure for those carbs. Anything more and you have issues.

I think the issue is electrical, but I have no idea what it could be. If your electric tach is freaking out at the same time the engine is dying, I'd say thats the tell tail sign.

Will

i have seen this issue with a msd coil before...but not on a datsun.
it was on a smallblock ford. it would run fine at speed, and most of the time for that matter. then all the sudden it would just stumble...and die. then it would take about a minute or so to get it fired back up with lots of cranking. it was a chrome blaster or blaster 2 coil...cant remember which. msd had me try another coil... then warrantied it. never had another issue

had the same tach issue as well
try another known good coil.

I still have the stock coil. Can I use that? Doesn't the MSD have an internal resistor? I have mine bypassed now.

Kyle

The stock coil will not work with the EI distributor - at least not for very long. Go with a correct 12V coil for EI, or more specifically one for a '79-81 Datsun 210 or 310 for your set-up.

Try swapping the stock coil in. If the issues go away the MSD one is the issue. I'd bet you can run the stock one for awhile before you run into any issues, you might be able to run it forever. I'd give it a shot and see what happens.

I've had odd MSD coil issues in the past as well. The coil would get hot and quit working no matter what I did. Once it cooled off, it would work fine for another 20 min or so.

Will

Looks like the coil was the culprit. Went and got another MSD Blaster coil. Purrs like a kitten. And the tach stays still as well. Not bouncing all over like before. I thought I read something about MSD coils and being mounted in a sideways position. Mine is mounted sideways.

Thanks all for the quick advise.

Kyle

If it's an oil filled coil, they are better off mounted vertically. In theory, if it has a 100% oil fill, it won't make a difference, but the real world may vary.
If you can, put the old coil in the new package and return it...Not totally honest, but justified. If they exchange it, then keep the new spare.

Well, I was hoping this would have gone away. after a few miles, my problems arose again. My car hasn't completely stalled like before but the Tach is bouncing all over, pegging the end sometimes. Runs rough, cuts out. New MSD coil, mounted in the VERTICAL position. Today went and bought another non MSD (Nissan) coil, and the same thing. But then, it will just start running great, needle on the tach stays still, and is responsive. Kind of random. Sometimes it starts, idles, and runs great. Others, it sputters, and is rough running. I'm really thinking it is an ignition issue, but I don't know what to test.

I have a GB dizzy. Stock nissan 12v coil, or MSD. Both run the same. Dave, you are building these dizzy's now, do you think it could have anything to do with the dizzy?

Car was running great up until the past month or so. I can't figure out what else to check?

Thanks for any advice.